IRSLetterDecoded

The 90-day clock that forgives nothing

One deadline in tax mail stands apart: when the IRS sends a notice of deficiency — the CP3219A or Letter 531 — you have 90 days to ask the U.S. Tax Court to decide whether you owe it. Not 'about 90.' Not extendable by anyone. Miss it, and the IRS assesses the full amount and the fight moves to pay-first-refund court.

How the clock runs

Starts: the date on the notice — 90 days, or 150 if the notice is addressed outside the United States.
Ends: on the 90th day; if that day is a Saturday, Sunday, or a legal holiday in the District of Columbia, it rolls to the next business day (§ 7503).
Mailing counts: a petition mailed by the deadline — U.S. postmark — is timely even if it arrives later (§ 7502). Certified mail turns that into proof.
During the 90 days (and while a timely case runs), the IRS generally cannot assess or collect the disputed amount (§ 6213(a)).

Filing, practically

Petitions are filed with the U.S. Tax Court in Washington, DC — increasingly through its online DAWSON system. The filing fee is $60 (waivable). Cases of $50,000 or less per year can elect the small-tax-case track: informal, faster, and decided without appeal. Most deficiency cases settle with IRS Appeals before any courtroom — filing the petition is what keeps that door, and the judge behind it, alive.

The trap

The 90 days do not pause for phone calls, amended returns, or a representative 'looking into it.' If the amount matters and the clock is running, file first and negotiate second — a timely petition preserves everything; a missed one preserves nothing.

The letter is decoded. Now answer it right.

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Questions

My notice says I can agree or partially agree — does answering stop the clock?

Signing agreement forms ends the matter for the agreed parts. But merely writing to the IRS, calling, or sending documents does not stop the 90 days. Only a filed Tax Court petition preserves the full fight.

What if the 90 days already passed?

The IRS will assess. The remaining road is pay-and-sue-for-refund in federal court — slower, and it starts with paying. This is the moment a tax attorney's read is worth real money.

Is Tax Court like regular court?

It's a specialized federal court, and the small-case track is designed for unrepresented taxpayers: plain procedures, no jury, judges who see tax math all day. For big or complex deficiencies, counsel remains the wise spend.